#!/usr/bin/env bash
# Inform the user of the output they can expect.

echo "common commands:"


# The following variables control how the command runs.
shell_binary=""     # A place to store the shell binary value
history_file=""     # A place to store the history file path
history_lines=1000  # The number of lines of history to search through
command_count=10    # The number of common commands to show

# Check whether you can determine the name of the shell binary
shell_regex="([^/]+$)"
if [[ $SHELL =~ $shell_regex ]]; then
    # Depending on the name of the shell binary, set the history filepath
    shell_binary=${BASH_REMATCH[1]}
    if [[ $shell_binary == "bash" ]]; then
        history_file=~/.bash_history
    elif [[ $shell_binary == "zsh" ]]; then
        history_file=~/.zsh_history
    fi
fi

# If you are searching through the bash history, you can look at the history file
# to get the most common commands
if [[ $shell_binary == "bash" ]]; then
    
    # Show the most commonly used commands
    tail "${history_file}" -n ${history_lines} \
        | sort \
        | uniq -c \
        | sed 's/^ *//' \
        | sort -n -r \
        | head -n ${command_count}

elif [[ $shell_binary == "zsh" ]]; then

    # Z shell shitory lines look like this:
    # : 1621135004:0;uname -a
    # Run the same command as above, and extract everything _after_ the
    # semicolon, which is the command text
    tail "${history_file}" -n ${history_lines} \
        | cut -d';' -f2 \
        | sort \
        | uniq -c \
        | sed 's/^ *//' \
        | sort -n -r \
        | head -n ${command_count}
else

    # show a warning to the user that you don't know where the history file
    # is for their shell
    echo "Sorry, I don't know where to find the history file for '${SHELL}'"
fi